From 6919e876561eb2729419212e7887b6d34748bc93 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Mon, 28 May 2018 17:39:23 -0500
Subject: [PATCH] Minor cleanup of multi-stepping logic

---
 Marlin/src/feature/pause.cpp |  2 +-
 Marlin/src/module/stepper.h  | 38 ++++++++++++------------------------
 2 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/Marlin/src/feature/pause.cpp b/Marlin/src/feature/pause.cpp
index fa06193ab9..d2188c7c7a 100644
--- a/Marlin/src/feature/pause.cpp
+++ b/Marlin/src/feature/pause.cpp
@@ -533,7 +533,7 @@ void resume_print(const float &slow_load_length/*=0*/, const float &fast_load_le
   // Move XY to starting position, then Z
   do_blocking_move_to_xy(resume_position[X_AXIS], resume_position[Y_AXIS], NOZZLE_PARK_XY_FEEDRATE);
 
-  // Set Z_AXIS to saved position
+  // Move Z_AXIS to saved position
   do_blocking_move_to_z(resume_position[Z_AXIS], NOZZLE_PARK_Z_FEEDRATE);
 
   // Now all extrusion positions are resumed and ready to be confirmed
diff --git a/Marlin/src/module/stepper.h b/Marlin/src/module/stepper.h
index d10b8c32ed..19c9d4b9b5 100644
--- a/Marlin/src/module/stepper.h
+++ b/Marlin/src/module/stepper.h
@@ -267,41 +267,28 @@ class Stepper {
     // Set direction bits for all steppers
     static void set_directions();
 
+    // Limit the speed to 10KHz for AVR
+    #ifndef STEP_DOUBLER_FREQUENCY
+      #define STEP_DOUBLER_FREQUENCY 10000
+    #endif
+
     FORCE_INLINE static uint32_t calc_timer_interval(uint32_t step_rate) {
       uint32_t timer;
 
       NOMORE(step_rate, uint32_t(MAX_STEP_FREQUENCY));
 
-      // TODO: HAL: tidy this up, use Conditionals_post.h
-      #ifdef CPU_32_BIT
-        #if ENABLED(DISABLE_MULTI_STEPPING)
-          step_loops = 1;
-        #else
-          if (step_rate > STEP_DOUBLER_FREQUENCY * 2) { // If steprate > (STEP_DOUBLER_FREQUENCY * 2) kHz >> step 4 times
-            step_rate >>= 2;
-            step_loops = 4;
-          }
-          else if (step_rate > STEP_DOUBLER_FREQUENCY) { // If steprate > STEP_DOUBLER_FREQUENCY kHz >> step 2 times
-            step_rate >>= 1;
-            step_loops = 2;
-          }
-          else {
-            step_loops = 1;
-          }
-        #endif
-      #else
-        if (step_rate > 20000) { // If steprate > 20kHz >> step 4 times
+      #if DISABLED(DISABLE_MULTI_STEPPING)
+        if (step_rate > STEP_DOUBLER_FREQUENCY * 2) { // If steprate > (STEP_DOUBLER_FREQUENCY * 2) kHz >> step 4 times
           step_rate >>= 2;
           step_loops = 4;
         }
-        else if (step_rate > 10000) { // If steprate > 10kHz >> step 2 times
+        else if (step_rate > STEP_DOUBLER_FREQUENCY) { // If steprate > STEP_DOUBLER_FREQUENCY kHz >> step 2 times
           step_rate >>= 1;
           step_loops = 2;
         }
-        else {
-          step_loops = 1;
-        }
+        else
       #endif
+          step_loops = 1;
 
       #ifdef CPU_32_BIT
         // In case of high-performance processor, it is able to calculate in real-time
@@ -309,8 +296,9 @@ class Stepper {
         timer = uint32_t(HAL_STEPPER_TIMER_RATE) / step_rate;
         NOLESS(timer, min_time_per_step); // (STEP_DOUBLER_FREQUENCY * 2 kHz - this should never happen)
       #else
-        NOLESS(step_rate, uint32_t(F_CPU / 500000U));
-        step_rate -= F_CPU / 500000; // Correct for minimal speed
+        constexpr uint32_t min_step_rate = F_CPU / 500000U;
+        NOLESS(step_rate, min_step_rate);
+        step_rate -= min_step_rate; // Correct for minimal speed
         if (step_rate >= (8 * 256)) { // higher step rate
           const uint8_t tmp_step_rate = (step_rate & 0x00FF);
           const uint16_t table_address = (uint16_t)&speed_lookuptable_fast[(uint8_t)(step_rate >> 8)][0],